Near-eye display device, augmented reality device, and viewing angle adjustment method

ABSTRACT

A near-eye display device includes a camera module, a display module and a rotating module. The camera module is configured for obtaining an image information along a direction of a first optical axis. The display module is configured for transmitting an image light of virtual information to a human eye along a second optical axis. The rotating module is configured for controlling the rotation of the camera module to change a position of the first optical axis, so as to switch the near-eye display device between a state of close-up view and a state of distant view. In the state of distant view, an angle between the first optical axis and the second optical axis is 25°. In the state of close-up view, the angle between the first optical axis and the second optical axis is less than or equal to 13°.

FIELD

The subject matter herein generally relates to displays, specifically tonear-eye display devices, augmented reality devices, and viewing angleadjustment methods of the near-eye display devices.

BACKGROUND

Augmented reality (AR) is a kind of display technology that integratesvirtual information with the real world. Existing AR display devicesusually include a camera module and a display module, the camera moduleis used to obtain images within a visual field of a user and the displaymodule is used to project virtual image to a preset position within thevisual field of the user according to the images obtained by the cameramodule.

However, existing camera modules and display modules may only be wellapplied to a state of distant view, when the observed object is in aclose-up view distance (for example, the distance between the observedobject and the human eye is less than 40 cm), the vertical viewing angleof the human eye will move down automatically. At this time, the focusof the human eye may move away from the center of the real sceneacquired by the camera module.

In addition, because a certain distance exists between the camera moduleand the display module, the optical axis of the camera module and theoptical axis of the display module are usually intersecting to have acertain included angle to match the display in the state of distantview, causing that the overlapping area between a shooting range of thecamera module and a display range of the display module becomes smallerin the state of close-range view, and thus the AR effect may not beachieved.

Therefore, there is room for improvement in the art.

BRIEF DESCRIPTION OF THE DRAWINGS

Implementations of the present disclosure will now be described, by wayof embodiment, with reference to the attached figures, wherein:

FIG. 1 is a side view of a near-eye display device in a state ofclose-up view in the related art.

FIG. 2 shows a shooting range of a camera module and a display range ofa display module of the near-eye display device in a state of close-upview in the related art.

FIG. 3 is a side view of a near-eye display device according to anembodiment of the present disclosure.

FIG. 4 is a relationship diagram between an angle of the camera moduleand a comfort level according to an embodiment of the presentdisclosure.

FIG. 5 is a side view of a shooting range of the camera module and adisplay range of the display module according to an embodiment of thepresent disclosure.

FIG. 6 is a partial side view of the camera module according to anembodiment of the present disclosure.

FIG. 7 is a partial side view of the display module according to anembodiment of the present disclosure.

FIG. 8 is a top view of an AR device according to an embodiment of thepresent disclosure.

FIG. 9 is a flowchart of a viewing angle adjustment method of thenear-eye display device according to an embodiment of the presentdisclosure.

DETAILED DESCRIPTION

It will be appreciated that for simplicity and clarity of illustration,where appropriate, reference numerals have been repeated among thedifferent figures to indicate corresponding or analogous elements. Inaddition, numerous specific details are set forth in order to provide athorough understanding of the embodiments described herein. However, itwill be understood by those of ordinary skill in the art that theembodiments described herein can be practiced without these specificdetails. In other instances, methods, procedures, and components havenot been described in detail so as not to obscure the related relevantfeature being described. Also, the description is not to be consideredas limiting the scope of the embodiments described herein. The drawingsare not necessarily to scale and the proportions of certain parts havebeen exaggerated to better illustrate details and features of thepresent disclosure.

Several definitions that apply throughout this disclosure will now bepresented.

The term “coupled” is defined as connected, whether directly orindirectly through intervening components, and is not necessarilylimited to physical connections. The connection can be such that theobjects are permanently connected or releasably connected. The term“outside” refers to a region that is beyond the outermost confines of aphysical object. The term “inside” indicates that at least a portion ofa region is partially contained within a boundary formed by the object.The term “substantially” is defined to be essentially conforming to theparticular dimension, shape or other word that substantially modifies,such that the component need not be exact. For example, “substantiallycylindrical” means that the object resembles a cylinder, but can haveone or more deviations from a true cylinder. The term “comprising,” whenutilized, means “including, but not necessarily limited to”; itspecifically indicates open-ended inclusion or membership in theso-described combination, group, series and the like.

“Optional” or “optionally” means that the subsequently describedcircumstance may or may not occur, so that the description includesinstances where the circumstance occurs and instances where it does not.

“Above” means one layer is located on top of another layer. In oneexample, it means one layer is situated directly on top of anotherlayer. In another example, it means one layer is situated over thesecond layer with more layers or spacers in between.

When a feature or element is herein referred to as being “on” anotherfeature or element, it can be directly on the other feature or elementor intervening features and/or elements may also be present. It willalso be understood that, when a feature or element is referred to asbeing “connected” or “attached” to another feature or element, it can bedirectly connected or attached to the other feature or element orintervening features or elements may be present.

FIG. 1 illustrates a near-eye display device 900 in the related art. Thenear-eye display device 900 includes a display module 91 and a cameramodule 93, the display module 91 includes a light transmitting waveguideplate 911 and a light engine 913. The near-eye display device 900 is adisplay device based on AR. The waveguide plate 911 is set in adirection of a human eye E looking at, and the light engine 913 is usedto irradiate image light on the waveguide plate 911, so that thewaveguide plate 911 can display the image light emitted by the lightengine 913 to the user, while transmitting light from a side away fromthe human eye E simultaneously. As a result, the human eye E can seeinformation of the real world and virtual information projected by thelight engine 913, that is, AR display.

The waveguide plate 911 is usually based on the principle of grating andtotal reflection, that is, the image light emitted by the light engine913 is transmitted on the waveguide plate 911, and is continuously totalreflected along both sides of the waveguide plate 911 under the actionof grating, and finally reflected into the human eye E. In such process,the image light emitted by the light engine 913 diffuses to form adisplay range 910 (as FIG. 2 shows) within the field of vision of thehuman eye E. Specifically, the display range 910 is an area where thedisplay module 91 can display the virtual information within the fieldof vision of the human eye E. Usually, the display range 910 only coverspart of the field of vision of the human eye E instead of the wholefield of vision, as a result, the display center point P1 of the displayrange 910 usually coincides with a gazing center point of the human eyeE, so as to achieve a better display effect.

For the near-eye display device 900, the display module 91 can onlyproject the virtual information to the human eye E, so as to superimposethe virtual information on the basis of the real world. However, withoutobtaining a real-world field of view, the image light displayed by thedisplay module 91 cannot be correlated with the real-world field ofview. In order to further realize an AR function, the virtualinformation should be superimposed at a proper position of thereal-world field of view. Therefore, the camera module 93 is needed tosynchronously obtain the view information of the human eye E, so thatthe display module 91 can interact with the view that the human eye E islooking at. In other words, an overlapping area between the viewinformation obtained by the camera module 93 (that is, a shooting area930 in FIG. 2 ) and the display area 910 is required, the overlappingarea is an effective range F1 that can realize the AR function.

For the near-eye display device 900, the camera module 93 is configuredfor obtaining the view information of the human eye E, but obviously thecamera module 93 cannot be set directly in front of the human eye E.Therefore, the camera module 93 is generally set above the human eye E,and an optical axis of the camera module 93 is tilted to a directionthat the human eye E is looking at. An angle θ between the direction andthe optical axis of the camera module 93 is usually 25°.

However, referring to FIG. 1 and FIG. 2 , the near-eye display device900 can only be applied to the state of distant view. In the state ofclose-up view, that is, a distance between the human eye E and anobserved object is less than 40 cm, the near-eye display device 900 maynot be able to realize the AR function.

Specifically, on the one hand, in the state of distant view, although anoptical axis of the display module 91 coincides with the direction thatthe human eye E is looking at, but there is an angle θ between theoptical axis of the display module 91 and the optical axis of the cameramodule 93, the angle θ is 25°. As a result, in the state of close-upview, the effective range F1 overlapped between the display area 910 andthe shooting area 930 will become small, resulting in the failure of ARfunction.

On the other hand, in the state of close-up view, the gazing point ofthe human eye E is usually shifted downward by 15°-20° to improve thecomfort of looking. That is, in the state of close-up view, the gazingcenter point P of the human eye E will deviate from the display centerpoint P1 of the display module 91, causing the display area 910 of thedisplay module 91 deviate upward from the line of sight of the human eyeE, or even out of the gazing center point P of the human eye E.

In order to realize AR function in the state of close-up view, FIG. 3illustrates a near-eye display device 100 according to an embodiment ofthe present disclosure. The near-eye display device 100 includes adisplay module 11, a camera module 13, and a rotating module 15. Thecamera module 13 is used to obtain an image information along adirection of a first optical axis L1. The display module 11 is used totransmit an image light of virtual information to the human eye E alonga second optical axis L2. The second optical axis L2 has a non-zeroincluded angle with the first optical axis L1. The rotating module 15 isconnected with the camera module 13, and is used to control the rotationof the camera module 13 to change an included angle θ between the firstoptical axis L1 and the second optical axis L2, so as to switch thenear-eye display device 100 between a state of close-up view and a stateof distant view. In the state of distant view, the angle θ between thefirst optical axis L1 and the second optical axis L2 is 25°. In thestate of close-up view, an angle α between the first optical axis L1 anda first direction X is 18°-25°, and the angle θ between the firstoptical axis L1 and the second optical axis L2 is less than or equal to13°.

Specifically, the first direction X is a direction that the human eye Elooks at in the state of distant view. In the state of close-up view,the direction that the human eye E will shift downward compared with thefirst direction X to improve the comfort level. In other to compensatefor the shift of the direction that the human eye E looks at and thereduction of the effective area overlapped between the display area ofthe display module 11 and the shooting area of the camera module 13 inthe state of close-up view. The rotating module 15 will control therotation of the camera module 13 to an appropriate angle, so as torealize the AR function in the state of close-up view.

The display module 11 includes a waveguide plate 111 and a light engine113. The light engine 113 is used to emit an image light to thewaveguide plate 111, the waveguide plate 111 is used to project theimage light to the human eye E, so that the human eye E can observe avirtual image from a side of the waveguide plate 111 away from the humaneye E. The waveguide plate 111 is perpendicular to the second opticalaxis L2, and the virtual image also intersects with the second opticalaxis L2. The position that the second optical axis L2 intersects with aplane of the virtual image is the geometric center of the display areaof the display module 11. The camera module 13 includes an imageacquisition device, and the first optical axis L1 is an orientationaligned by the camera module 13, that is, the geometric center of theimage information obtained by the camera module 13.

FIG. 4 illustrates a relationship between the angle α of the cameramodule 13 and a user's average comfort level in a case of the distancebetween the human eye E and the observed object is 40 cm. Specifically,the comfort level refers to a length of time the user can maintain aposition in which the near-eye display device 100 is in use untilfatigue occurs. For example, when the comfort level is 5 points, theuser begins to get tired after using the near-eye display device 100 forabout 5-10 minutes; when the comfort level is 6 points, the user beginsto get tired after using the near-eye display device 100 for about 10-15minutes; when the comfort level is 7 points, the user begins to gettired after using the near-eye display device 100 for about 15-20minutes, and so on; when the comfort level is 10 points, the user beginsto get tired after using the near-eye display device 100 longer than 30minutes. Taking the 6 points average comfort level as the minimum usingstandard, then the angle α between the first optical axis L1 and thefirst direction X is 18°, and when the average comfort level is 10points, the angle α between the first optical axis L1 and the firstdirection X is 25°. Therefore, in the state of close-up view, in orderto ensure the comfort of use, the angle α between the first optical axisL1 and the first direction X is 18°-25°.

FIG. 5 illustrates the relationship between the display area of thedisplay module 11 and the shooting area of the camera module 13. In thestate of close-up view, when the angle θ between the first optical axisL1 of the camera module 13 and the second optical axis L2 of the displaymodule 11 is 13°, the display area is completely covered by the shootingarea, and an edge of the display area coincides with an edge of theshooting area. As a result, in order to realize the AR function, theangle θ between the first optical axis L1 and the second optical axis L2is less than or equal to 13°. Otherwise, when the angle θ is 8°, thecenter of the display area of the display module 11 coincides with thecenter of the shooting area of the camera module 13.

Referring to FIG. 3 , an angle β between the second optical axis L2 andthe first direction X is Specifically, on the one hand, in the state ofclose-up view, the angle α is 18°-25°, and the angle θ is less than orequal to 13°, as a result, when the angle α is 18°, the angle β is atleast 5°. On the other hand, since the waveguide plate 111 isperpendicular to the second optical axis L2, and the waveguide plate 111is set in front of the human eye E, in order to prevent the waveguideplate 111 from being too inclined to touch the human eye E, the angle βbetween the second optical axis L2 and the first direction X is at most12°, that is, the angle θ is actually 6°-13°.

In this embodiment, a variety of angle collocation can be includedbetween the display module 11 and the camera module 13. For example,when the angle β between the second optical axis L2 and the firstdirection X is 5°, in the state of close-up view, the angle θ betweenthe first optical axis L1 and the second optical axis L2 is 13°, and theangle α between the first optical axis L1 and the first direction X is18°. When the angle β is 6°, in the state of close-up view, the angle θcan be 13°, and the angle α is 19°; or the angle θ can be 12°, and theangle α is 18°. When the angle β is 7°, in the state of close-up view,the angle θ can be 13°, and the angle α is 20°; or the angle θ can be12°, and the angle α is 19°; or the angle θ can be 11°, and the angle αis 18°, etc.

The following will be illustrated in the situation when the angle β is5°, the angle θ is 13°, and the angle α is 18°. In other embodiments, itmay also be the other situations illustrated above, that is, the angle αis 18°-25°, the angle θ is 5°-12°, and the angle θ is less than or equalto 13°.

The rotating module 15 may include a rotating motor for adjusting thecamera module 13 to the state of close-up view, or adjusting from thestate of close-up view to the state of distant view. In the state ofdistant view, the angle θ between the first optical axis L1 and thesecond optical axis L2 is 25°.

The near-eye display device 100 also includes a processor 14, theprocessor 14 is electrically connected to the rotating module 15 totransmit a control signal to the rotating module 15 to control therotation angle of the camera module 13. The processor 14 can also beelectrically connected to the display module 11 and the camera module13, so as to control the display module 11 to project the image lightaccording to the image information obtained by the camera module 13,thus to realize the AR function.

The near-eye display device 100 can also include an eye tracking module17 to observe the state of the human eye E, the eye tracking module 17is electrically connected to the processor 14. The processor 14 is usedto generate the control signal according to the state of the human eyeE, and the rotating module 15 is used to control the camera module 13switch between the state of distant view and the state of the close-upview according to the control signal.

Specifically, in the state of close-up view, an angle of view of thehuman eye E will be deflected by a certain angle from the horizontalview in the first direction X, so an eyeball of the human eye E willalso deflect a certain angle. The eye tracking module 17 can obtain animage of the human eye E, and the processor 14 can judge whether thehuman eye E is looking at objects in the close-up view, and then controlthe camera module 13 to switch between the state of distant view and thestate of the close-up view.

The eye tracking module 17 can include an infrared light source and asensor. The infrared light source is used to emit infrared light towardthe human eye E, and the sensor is used to sense the infrared lightreflected from the human eye E to obtain the position information of theeyeball of the human eye E. Specifically, an eye surface of the humaneye E includes iris and cornea, and the boundary between the iris andcornea has a certain angle. By capturing the infrared light reflectedfrom the human eye E, the eye tracking module 17 can obtain the boundaryposition between the iris and cornea, so as to determine the position ofthe eyeball of the human eye E, and thus determine the gazing directionof the human eye E.

The near-eye display device 100 can also include a distance measuringmodule 19 to detect a distance between the human eye E and an observedobject. The distance measuring module 19 is electrically connected tothe processor 14. The processor 14 generates the control signalaccording to the distance, and the rotating module 15 is used to controlthe camera module 13 switch between the state of distant view and thestate of the close-up view according to the control signal.

Specifically, the distance measuring module 19 can be a time-of-flight(ToF) ranging device, by transmitting and receiving laser lightreflected from the observed object, the distance can be determinedaccording to the round-trip time of the laser light. When the distancebetween the human eye E and the observed object is within a distancerange of the close-up view, such as 40 cm, the rotating module 15 willswitch the camera module 13 to the state of close-up view.

In other embodiments, the user can also directly control the rotatingmodule 15 to control the switch between the state of distant view andthe state of close-up view. Or the near-eye display device 100 can alsoinclude other detecting device to detect whether the near-eye displaydevice 100 is in a situation of close-up view, then control the rotationof the camera module 13 to switch between the state of distant view andthe state of the close-up view.

In this embodiment, the near-eye display device 100 can only include oneof the eye tracking module 17 and the distance measuring module 19, orinclude both of the eye tracking module 17 and the distance measuringmodule 19, or include one or combination of the eye tracking module 17,the distance measuring module 19 and other detecting devices.

FIG. 6 and FIG. 7 illustrate a partial side view of the near-eye displaydevice 100 according to an embodiment of the present disclosure. Thenear-eye display device 100 also includes a shell 12, the shell 12includes an upper shell 121 and a protective cover 123, the light engine113 and the camera module 13 are set in the upper shell 121, thewaveguide plate 111 is covered by the protective cover 123, and an endof the protective cover 123 away from the upper shell 121 tilts in adirection of the human eye E, so that an angle γ between a wall 1231 ofthe protective cover 123 facing the human eye E and the first directionX is 78°-85°.

Specifically, the upper shell 121 is used to protect the light engine113 and the camera module 13, the protective cover 123 is used toprotect the waveguide plate 111, that is, the protective cover 123 isset parallel to the waveguide plate 111. The upper shell 121 can be madeof an opaque material, and the protective cover 123 is made of atransparent material. A hole 122 can be defined in the upper shell 121corresponding to the camera module 13 to facilitate image acquisition.

By setting the rotating module 15, the camera module 13 can switchbetween the state of distant view and the state of close-up view, sothat the near-eye display device 100 can be applied to the situations ofdistant view and close-up view. By setting the angle α between the firstoptical axis L1 of the camera module 13 and the first direction X is18°-25°, the comfort level of the user can be improved. By setting theangle θ between the first optical axis L1 of the camera module 13 andthe second optical axis L2 of the display module 11 is less than orequal to 13°, the display area of the display module 11 can becompletely covered by the shooting area of the camera module 13, so thatthe AR function can be realized within the display area. By setting theeye tracking module 17 and the distance measuring module 19, thesituation of the near-eye display device 100 can be judged, so as tocontrol the camera module 13 to switch between the state of distant viewand the state of close-up view, thus expanding the use range of thenear-eye display device 100.

FIG. 8 illustrates an AR device 200 according to an embodiment of thepresent disclosure. The AR device 200 includes the near-eye displaydevice 100 and a fixing device 201. The fixing device 201 is used to fixthe near-eye display device 100 to a user's head so that the human eyeis aligned with the display module 11.

In this embodiment, the fixing device 201 is connected to the shell 12.Specifically, the fixing device 201 is connected to the upper shell 121.The fixing device 201 can be a belt used to fix the near-eye displaydevice 100 to the user's head. In other embodiments, the fixing device201 can also be a pair of legs to support the near-eye display device100 in front of the human eye like a pair of glasses.

In this embodiment, the AR device 200 also includes a battery 203, thebattery 203 is electrically connected to the near-eye display device 100to provide power to the near-eye display device 100. The battery 203 canbe set on the fixing device 201 to balance the weight of the AR device200, or can be set independently and wired to the near-eye displaydevice 100.

Referring to FIG. 9 , a flowchart is presented in accordance with anexample embodiment which is thus illustrated. The example method isprovided by way of example, as there are a variety of ways to carry outthe method. The method described below can be carried out using theconfigurations illustrated in FIGS. 3 , for example, and variouselements of these figures are referenced in explaining example method.Each block shown in FIG. 9 represents one or more processes, methods, orsubroutines, carried out in the exemplary method. Additionally, theillustrated order of blocks is by example only and the order of theblocks can change according to the present disclosure. The exemplarymethod can begin at block 301.

At block 301, a camera module 13 is provided, the camera module 13 isused to obtain an image information along a direction of a first opticalaxis L1.

At block 302, a display module 11 is provided, the display module 11 isused to transmit an image light of virtual information to a human eye Ealong a second optical axis L2.

At block 303, the camera module 13 can be rotated to switch between astate of close-up view and a state of distant view. In the state ofclose-up view, an angle α between the first optical axis L1 and a firstdirection X is 18°-25°, and the angle θ between the first optical axisL1 and the second optical axis L2 is less than or equal to 13°.

Before the block 303, the camera module 13 can be rotated to the stateof distant view. In the state of distant view, the angle θ between thefirst optical axis L1 and the second optical axis L2 is Specifically, inthe state of distant view, the angle θ should be set to 25° to ensurethat the AR function can be realized in the state of distant view.

Before the block 303, a movement state of the human eye E can betracked, so as to rotate the camera module 13 to either the state ofclose-up view or the state of distant view according to the movementstate of the human eye E. Specifically, the human eye E will deflectdownward 15°-20° in the situation of close-up view, by tracking themovement state of the human eye E, the current situation can bedetermined as close-up view situation when the human eye E is deflecteddownward, so as to control the rotation of the camera module 13 from thestate of distant view to the state of close-up view.

Before the block 303, a distance between the human eye E and an observedobject can be measured, so as to rotate the camera module 13 to eitherthe state of close-up view or the state of distant view according to thedistance. Specifically, in the state of close-up view, the distancebetween the human eye E and the observed object will be less than acertain value, such as less than By measuring the distance, it can bedetermined whether the current situation is a close-up view situation,so as to determine whether to control the rotation of the camera module13 from the state of distant view to the state of close-up view.

In this embodiment, both of the movement state and the distance can beobtained by the near-eye display device 100, or only one method ofobtaining the movement state and obtaining the distance is used to judgethe situation of the near-eye display device 100, and then determine therotation of the camera module 13. In other embodiments, other detectingmethod can also be used to detect the situation of the near-eye displaydevice 100.

By rotating the camera module 13 to switch between the state of distantview and the state of close-up view, the near-eye display device 100 canbe applied to both situation of the distant view and the close-up view,thus expanding the use range of the near-eye display device 100.

It is to be understood, even though information and advantages of thepresent exemplary embodiments have been set forth in the foregoingdescription, together with details of the structures and functions ofthe present exemplary embodiments, the disclosure is illustrative only.Changes may be made in detail, especially in matters of shape, size, andarrangement of parts within the principles of the present exemplaryembodiments to the full extent indicated by the plain meaning of theterms in which the appended claims are expressed.

What is claimed is:
 1. A near-eye display device, comprising: a cameramodule configured for obtaining an image information along a directionof a first optical axis; a display module configured for transmitting animage light of virtual information to a human eye along a second opticalaxis; and a rotating module connected with the camera module, whereinthe rotating module is configured for controlling a rotation of thecamera module to change a position of the first optical axis, so as toswitch the near-eye display device between a state of close-up view anda state of distant view, in the state of distant view, an included anglebetween the first optical axis and the second optical axis is 25°, andin the state of close-up view, the included angle is less than or equalto 13°.
 2. The near-eye display device of claim 1, wherein an anglebetween the first optical axis and a first direction is 18°-25° in thestate of close-up view, and the first direction is a direction of ahead-up view of the human eye in the state of distant view.
 3. Thenear-eye display device of claim 2, wherein the display module comprisesa light engine and a waveguide plate, the light engine is configured foremitting an image light, the waveguide plate is configured fortransmitting the image light to the human eye, and the waveguide plateis substantially perpendicular to the second optical axis.
 4. Thenear-eye display device of claim 3, further comprising a shell, theshell comprising an upper shell and a protective cover; wherein thelight engine and the camera module are in the upper shell, theprotective cover covers the waveguide plate, and an end of theprotective cover away from the upper shell tilts in a direction of thehuman eye, so that an angle between a wall of the protective coverfacing the human eye and the first direction is 78°-85°.
 5. The near-eyedisplay device of claim 1, further comprising a processor, wherein theprocessor is electrically connected to the rotating module, and isconfigured for transmitting a control signal to the rotating module tocontrol a rotation angle of the camera module.
 6. The near-eye displaydevice of claim 5, further comprising an eye tracking module configuredfor determining a state of the human eye; wherein the eye trackingmodule is electrically connected to the processor, the processor isconfigured for generating the control signal according to the state ofthe human eye, and the rotating module is configured for controlling thecamera module switch between the state of distant view and the state ofclose-up view according to the control signal.
 7. The near-eye displaydevice of claim 5, further comprising a distance measuring moduleconfigured for detecting a distance between the human eye and anobserved object; wherein the distance measuring module is electricallyconnected to the processor, the processor is configured for generatingthe control signal according to the distance, and the rotating module isconfigured for controlling the camera module switch between the state ofdistant view and the state of close-up view according to the controlsignal.
 8. An augmented reality (AR) device, comprising: a near-eyedisplay device, comprising: a camera module configured for obtaining animage information along a direction of a first optical axis; a displaymodule configured for transmitting an image light of virtual informationto a human eye along a second optical axis; and a rotating moduleconnected with the camera module, the rotating module is configured forcontrolling a rotation of the camera module to change a position of thefirst optical axis, so as to switch the near-eye display device betweena state of close-up view and a state of distant view; and a fixingdevice configured for fixing the near-eye display device to a user'shead so that the human eye is aligned with the display module, wherein,in the state of distant view, an angle between the first optical axisand the second optical axis is 25°, and in the state of close-up view,the angle between the first optical axis and the second optical axis isless than or equal to 13°.
 9. The AR device of claim 8, wherein an anglebetween the first optical axis and a first direction is 18°-25° in thestate of close-up view, and the first direction is a direction of ahead-up view of the human eye in the state of distant view.
 10. The ARdevice of claim 9, wherein the display module comprises a light engineand a waveguide plate, the light engine is configured for emitting animage light, the waveguide plate is configured for transmitting theimage light to the human eye, and the waveguide plate is perpendicularto the second optical axis.
 11. The AR device of claim 10, wherein thenear-eye display device further comprises a shell, the shell comprisesan upper shell and a protective cover; the light engine and the cameramodule are in the upper shell, the protective cover covers the waveguideplate, and an end of the protective cover away from the upper shelltilts in a direction of the human eye, so that an angle between a wallof the protective cover facing the human eye and the first direction is78°-85°.
 12. The AR device of claim 11, wherein the fixing device isconnected to the shell.
 13. The AR device of claim 8, further comprisinga battery, wherein the battery is electrically connected to the near-eyedisplay device.
 14. The AR device of claim 8, wherein the near-eyedisplay device further comprises a processor, wherein the processor iselectrically connected to the rotating module, and is configured fortransmitting a control signal to the rotating module to control therotation angle of the camera module.
 15. The AR device of claim 14,wherein the near-eye display device further comprises an eye trackingmodule configured for determining a state of the human eye; wherein theeye tracking module is electrically connected to the processor, theprocessor is configured for generating the control signal according tothe state of the human eye, the rotating module is configured forcontrolling the camera module switch between the state of distant viewand the state of close-up view according to the control signal.
 16. TheAR device of claim 14, wherein the near-eye display device furthercomprises a distance measuring module configured for detecting adistance between the human eye and an observed object; wherein thedistance measuring module is electrically connected to the processor,the processor is configured for generating the control signal accordingto the distance, the rotating module is configured for controlling thecamera module switch between the state of distant view and the state ofclose-up view according to the control signal.
 17. A viewing angleadjustment method of a near-eye display device, comprising: providing acamera module, which is configured for obtaining an image informationalong a direction of a first optical axis; providing a display module,which is configured for transmitting an image light of virtualinformation to a human eye along a second optical axis; rotating thecamera module to switch the near-eye display device between a state ofclose-up view and a state of distant view, wherein, in the state ofdistant view, an angle between the first optical axis and the secondoptical axis is 25°, and in the state of close-up view, the anglebetween the first optical axis and the second optical axis is less thanor equal to 13°.
 18. The method of claim 17, wherein rotating the cameramodule to switch the near-eye display device between the state ofclose-up view and the state of distant view further comprises: rotatingthe camera module to the state of close-up view, wherein an anglebetween the first optical axis and a first direction is 18°-25° in thestate of close-up view, wherein the first direction is a direction thatthe human eye looks at in the state of distant view.
 19. The method ofclaim 17, further comprising: tracking a movement state of the humaneye; and rotating the camera module to either the state of close-up viewor the state of distant view according to the movement state of thehuman eye.
 20. The method of claim 17, further comprising: measuring adistance between the human eye and an observed object; and rotating thecamera module to either the state of close-up view or the state ofdistant view according to the distance.